Wind power installations may have a generator and converter system divided into four independent branches. The generator and converter branches can be selectively connected by switches. Upon a failure of a converter component in one branch, that component is disconnected by opening of switches and the current path is connected to corresponding components of the other branches. The corresponding converter components in the other branches are automatically acted upon with a higher level of output power. However, in order to prevent overloading of the remaining intact converter components, those components must be over-dimensioned by about 20% so that even when those remaining components must supply the output power of a failed component, the components are not overloaded.
WO 2006/107548 A1 describes a power converter system adapted to operate in a normal mode and in a fault mode. The converter system has a plurality of parallel converters, referred to as “bridges”. In the event of a fault of a bridge the fault mode is entered and the faulty bridge is bypassed.